1. Field of the Invention
The field of art to which the invention pertains includes the field of internal combustion engine fuel systems, particularly with respect to a multi-mixture fuel system.
2. Description of the Prior Art
One approach for minimizing automotive pollution, without the use of expensive catalytic converters or thermal reactors to meet strict emission standards, has been the use of a stratified-charge engine. The stratified-charge engine operates on mixtures of fuel that are considerably more "lean" (a high ratio of air to gasoline) than standard engines presently utilize. The result is more complete combustion in the engines and greater reduction of polluting exhaust gases escaping from the vehicle tailpipe. In the stratified-charge engine, a mixture of fuel that would ordinarily be too lean for ignition by conventional spark ignition, is coaxed into burning by the ignition of an adjoining layer of much richer fuel. One technique for accomplishing this has been the addition of a small combustion chamber to accommodate the richer mixture at the top of each cylinder. This additional small chamber contains the spark plug and is equipped with its own intake valve. As the piston descends, the rich fuel mixture from one carburetor is drawn into the small combustion chamber near the spark plug. A leaner mixture from a second carburetor is fed into the main combustion chamber. The piston compresses both charges and in addition forces back most of the richer mixture in the small combustion chamber which may have seeped into the main chamber. The spark plug then fires the richer mixture which burns, igniting the adjoining lean mixture. Then, the expanding gases push the piston down and as the piston moves up again, the piston forces the spent gases through the open exhaust valve. The stratified-charge engine, in comparison to conventional engines, requires an extra carburetor, the additional parts needed to open and close a second intake valve on each cylinder, and the formation of the additional small combustion chamber adjacent to each main chamber.
Certain problems are encountered with the stratified-charge engines in changing speeds and loads due to the varying air and fuel speed ratios, particularly in the small combustion chamber. This causes difficulties in obtaining uniform acceleration rates.
Attempts have been made to improve combustion through the employment of a combined fuel injection system together with a carbureted fuel-air mixture. The approach has been to vary greatly both the amount of injected fuel as well as the timing of the injection, while simultaneously varying the amount and ratio of the carbureted fuel-air ratio. The complexity of such systems make them extremely sensitive and cause difficulty in obtaining satisfactory uniformity in required changes of speed and load. Furthermore, the major changes from current design of engines necessary to incorporate such design would be extremely expensive.
Known prior art includes U.S. Pat. Nos. 2,184,357; 2,534,346; 3,154,059; 3,294,072; 3,315,650; and 3,439,656.
The present invention operates on a mixture of fuel that is considerably more lean than standard engines presently operate on. Virtual complete combustion of the fuel is accomplished without the addition of an additional carburetor or a second intake valve in each cylinder. The present invention does not use a complex fuel injection system. The present invention can be utilized with standard internal combustion engines and modification thereof is relatively simple. Reduction of polluting exhaust gases is accomplished through the virtually complete combustion of the fuel.